Start with a background that will approximately match the color you’re going for. If you want cherry red, search for cherry red paper or cherry red paint. But what if all you can find is a maroon, or perhaps a red that’s not nearly cherry but rather a touch too pink? Ideally you’d match the background perfectly, but in practice that’s a pretty tall order. For our purposes, as long as you’re in the same color family you’ll be fine. After all, you’re going to use Photoshop a little later to make the match spot on.
So why not just shoot it on white? If you’re going to swap out the background color for a digitally “perfect” color, then why not just shoot the picture on white in the first place? Well, because the closer you can get in camera, the more accurate the finished image will appear after you’ve put it through the ringer in post.
Namely, all those white reflections from the white highlights as light bounces from the white paper back onto the subject. In the case of this yellow tomato, starting with it on yellow paper—even if it’s not the exactly perfect yellow paper—makes it much easier to make a seamless blend in post. All those little highlights around the edges of the subject are tinted yellow rather than white, and white would be a dead giveaway that the shot wasn’t actually made on a matching background. It would simply look fake.
With an appropriate background in hand, it’s time to snap the picture. You can light it essentially however you’d like, whether that’s a large softbox, sidelight from a window, or a snooted spotlight for a dramatic effect. The only lighting you’d be best to avoid is a raking light that casts a large shadow across the bulk of the background. In fact, any lighting angle that produces prominent, dark shadows is less than desirable, simply because it’s a little trickier to deal with in the next step.
The next step is to bring the shot into the computer and open it up in Photoshop. I immediately duplicate the image onto a new layer. From here, there are a couple of easy options for making the background match perfectly. You could use the Replace Color sliders (found under Adjustments on the Image menu) to dial it in fairly close, or you could use the Match Color tool—found just below Replace Color on the Image>Adjustments menu. It’s the perfect tool when you’ve got an exact target color in mind.
To use Match Color, start by creating a selection to separate the subject from the background. You can refine it too, and then save it using Save Selection on the Selection dropdown menu. This will come in handy a bit later.
Next, deselect the outline, and create a new selection using a magic wand or the lasso tool, or even a marquee. The important thing is, this selection should only contain an area of the ideal new background color. Which means, in the case of my yellow tomato shot, for instance, that I can just make a little selection of the tomato color that I’d like to use in the new background. I’m careful not to select a highlight area, or something with less than ideal color. Just a little swatch of perfect tomato color will do.
With this selection still active, open the Match Color tool in the Image>Adjustments menu. Starting from the top of the window, check the box that says “Ignore Selection when Applying Adjustment.” This will apply the new color across the entirety of the image, not just the portion that’s selected. The selection comes into play farther down the page, below Image Statistics. Keep the checkbox checked for “Use Selection in Source to Calculate Colors” and uncheck the second checkbox about using the selection in the target to calculate the adjustment. Next make sure the source is the image file you’re working on, and the layer it’s applying to is the active layer—Layer 1. You can use the sliders under Image Options to fine-tune the match, but if your selection was appropriate you probably won’t have to, particularly with light, bright colors. Click OK and take a look at your new image.
Sure enough, the background is now an all but perfect match for the color of the tomato. But there’s a wash of color over the whole shot, tomato and all. Here’s where that previous selection comes in. Load the subject outline selection in the Selection menu (via Load Selection) and then click the Create Layer Mask icon in the layers palette. This will use the outline selection to create a layer mask on this top layer, revealing the original subject tonality from the layer below.
At this point, the image should look pretty great. You can always dial down the new background color a bit simply by adjusting the opacity of the layer. And if you’re having any issues with the transition from shadow to background as I was, you can modify that now as well. In my case, simply setting the top “new color” layer to Darken made the shadow transition perfect. On an image with a darker background and a lighter shadow, a little more refinement may be necessary by adjusting the layer mask and blending modes.
Ultimately, the Match Color tool makes perfecting this color on color approach pretty easy. And it ensures that you’re actually matching the exact colors in the image, rather than trying to approximate the colors by eye.